某同学用如图1所示装置做探究“弹簧伸长和所受拉力关系”的实验．他先在弹簧下端挂上一个钩码，然后逐个增加钩码，测出弹簧下端指针对应所指的标尺刻度，所得数据列表如下：
| 钩码重G/N | 1.00 | 2.00 | 3.00 | 4.00 | 5.00 |
| 标尺刻度x/l0-2m | 22.94 | 26.82 | 31.78 | 34.66 | 38.60 |
（2）根据关系曲线可确定：弹簧伸长与所受拉力成______关系．这根弹簧的劲度系数为______N/m，原长为______cm．
（1）利用描点法得出图象如下所示：
（2）根据图象可知弹簧总长度和弹簧拉力关系图线为直线，因此弹簧伸长与所受拉力成正比关系，图线的斜率大小等于弹簧的劲度系数，图象与纵坐标的交点为弹簧的原长，根据图象有：弹簧的劲度系数k=25.5～26.5N/m，弹簧的原长为：l=18.8～19.2cm．
故答案为：正比，25.5～26.5，18.8～19.2．
用方框中所给单词或短语的适当形式填空，使短文通顺、正确连贯，每个单词或短语限用一次。
There are many ways to save the environment if you would like. In this passage, you can find some ways. Plant more trees. Choose a right 小题1:________ near your house or workplace. 小题2:________ there’s any rule stopping you growing trees in that area, go ahead and grow trees. Plant a tree every month and小题3:________ your friends and classmates to join you. Have more and more trees 小题4:________ and there will come a day when you have green land thanks to your hard work. Walk more and drive less. Choose to walk 小题5:________ drive your car. Walk or ride a bicycle to work if it’s not very far. Not only cycling but walking is good exercise. And each time you avoid using your car, you’re doing something 小题6:________ to cut down air pollution. You are saving fuel, saving money and keeping fit as well. Save water. Water is very important for living things. It’s 小题7:________ who use and pollute it. The simplest way to save water is turning 小题8:________ water taps after use. When you visit a beach, make sure that you don’t throw waste around. Do not pollute rivers 小题9:________ dropping garbage or other waste. Water is so precious, so we 小题10:________ waste or pollute it. |